As代P点缺陷对KDP晶体近紫外光损伤的影响

通过基于第一性原理的CASTEP软件计算发现,KDP晶体中As代P点缺陷的形成能约是4.0 eV,说明晶体中比较容易形成这种点缺陷.通过模拟点缺陷形成前后晶体的电子结构和能态密度发现,As替代P后,晶体能带宽度变为6.2 eV,这有可能会造成晶体对波长为355 nm的双光子吸收.As替代P后,As—O四面体体积增加,有利于金属离子以填隙的方式进入晶体,间接影响晶体光损伤阈值.

Effect of As substituting for P in KDP crystal on the near ultraviolet laser-induced damage

The electronic structure and energy state density of As substituting P in KPD crystal was studied by first principles. The calculated formation of As substituting for P is about 4.0 eV, it is easier to form in the crystal. The point defect narrows down the energy gap to about 6.2 eV, it corresponds to a two-photon absorption of 355 nm. The As—O tetrahedral volume increases, which contributes to metal ions in interstitial way into crystal, and may indirectly effect the optical damage.